Comparative linguistics -- the study of the history and
evolution
of
languages.

Psycholinguistics -- study of language from a cognitive and
developmental
view.

Sociolinguistics -- the study of language as it pertains to
social
classes, ethnic groups,
genders...

Phonetics -- the study of phonemes.

Phonemes -- the sounds of a language.

Syntax -- the grammar of a language.

Morphology -- the study of morphemes -- usually seen as a part
of
syntax.

Morphemes -- word stems and affixes, i.e. units of meaning in a
language.

Semantics -- the study of the meaning of language.

Lexicology -- the study of words -- a part of semantics.

The Top Twelve Languages

These languages have over 100 million each, inc. non-native speakers
-- although the actual numbers are difficult to estimate!
If you knew all 12 of these, you could probably communicate with more
than
2/3 of the world!

1st/2nd (tie):

Mandarin Chinese (Putonghua) -- 1 billion

English -- 1 billion (the world's most popular second language)

3rd: Hindu-Urdu (two dialects, each with a different
alphabet) --
900 million.

4th: Spanish -- 450 million.

5th: Russian -- 320 million.

6th/7th (tie):

Arabic -- 250 million.

Bengali -- 250 million.

8th: Portuguese -- 200 million.

9th: Malay-Indonesian (two dialects) -- 160 million.

10th: Japanese -- 130 million.

11th/12th (tie):

French -- 125 million

German -- 125 million

Language Families

There are a number of ways of classifying the thousands of languages
of our world. What follows is based on Greenberg's system, a
recent
classification which is still controversial. If you
would
like to see maps of these families, click
here. Some of the larger examples of each category have an
estimated
population in brackets; a second number indicates an estimate of
non-native
speakers.